Synonymy of Leonomyrma Arnoldi 1968 with Chalepoxenus Menozzi 1922 (Hymenoptera: Formicidae).

Reprinted from PSYCHE, Vol. 94, Nos. 1-2, 1987

SYNONYMY OF LEONOMYRMA ARNOLDI 1968

WITH CHALEPOXENUS MEHOZZl 1922

(HYMENOPTERA: FORMICIDAE)*

By Alfred Buschinger

Institut fiir Zoologie, Fachbereich Biologic,

der Technischen Hochschule, D 6100 Darmstadt,

Federal Republic of Germany.

Arnoldi (1968) erected the genus Leonomyrma for a single new
species, L. spinosa, which he had collected in July, 1949, near
Peremetriaja, East-Kasachstan (USSR), at the lower course of Ural
River. Up until present, only the type series of 4 $9 and 14 ^$ have
been known; no $ $ were found. In the course of a study in mor-
phology and behavior of several species of the ant genus Chale-
poxenus, I came across the description of Leonomyrma. A direct
comparison of its holotype ($) and an allotype (Q) with material of
two Chalepoxenus species, C. muellerianus (Finzi) (= C. gribodoi
Menozzi) and C. kutteri Cagniant, clearly revealed the synonymy of
the two genera.

Genus Chalepoxenus

Chalepoxenus Menozzi, 1922: 257, worker, female. Type species by original designa-
tion: C. gribodoi.

Leptothorax (Temnothorax) muellerianus Finzi, 1921: 118, synonymized with
Chalepoxenus by Miiller 1923: 98.

C. gribodoi Menozzi, 1922: 257, synonymized with C. muellerianus (Finzi) by Kutter
(1973).

Leonomyrma Arnoldi, 1968: 1809, female, male. Type species: L. spinosa, mono-
basic. NEW SYNONYMY.

Since the original description of Leonomyrma was published in
Russian, I provide an English translation of its main contents:

''Leonomyrma K. Arnoldi gen. n. (Leptothoracini)"
"Type of the genus: Leonomyrma spinosa K. Arnoldi sp. n.
Female: Head elongate rectangular. Antennae 12-jointed,

* Manuscript received by the editor August 14, 1986.

117

118 Psyche [Vol.94

mandibles triangular with dentate masticatory border. Frontal
carinae long and straight, not forming scrobes for hiding the
antennal scapes. Epinotum with two long spines. Petiolar
nodes rounded above, low, petiole with a conspicuous ventral
tooth, postpetiole with a long spine. The femora somewhat
swollen. Erect hairs of the body long, fine, pubescence only
present in legs and scapes. Wings with reduced venation, with a
long, closed cubital cell.

"Male: Antennae 13-jointed, the long, slender scape over-
reaching the occipital margin, club 4-segmented, not shorter
than the remainder of the funiculus. Eyes very large, convex.
Masticatory border of mandibles dentate. Thorax narrow, with
Mayrian furrows and strong epinotal spines. Hairs and wings
as in the female."

The description of the new species, L. spinosa, contains some mea-
surements of the holotype $:

"Head length 0.85 mm, width 0.70, scape length 0.60, length of
eye 0.30, thorax length 1.15, width 0.60, height 0.70, length of
petiole 0.30, width 0.29, height without ventral tooth 0.36,
postpetiole length 0.30, width 0.47 mm.

"Female: Head elongate, 1.5 times longer than wide, with
nearly straight lateral margins, with distinct anterior and more
rounded posterior corners. Eyes much larger than the genae.
Clypeus moderately vaulted, slightly concave in the middle of
the anterior margin, with an indistinct central carina. Frontal
triangle impressed, smooth, indistinctly confined. Antennal
club 3-segmented, only slightly shorter than the remainder of
the funiculus. Last segment (like in the male) about the length
of the two preceding ones together. Scape not fully reaching
the occipital margin. Segment 3 to 7 of funiculus wide, not
longer than wide. The long frontal carinae reaching behind the
hind margin of the eyes. Thorax slender, elongate, somewhat
flat above, anterior part of mesonotum narrowing, not cover-
ing the pronotal shoulders. Epinotal spines strong, longer than
half their basal distance. Petiole short, massive, in profile with
descending anterior and rounded upper surface, with a big
tooth below. Postpetiole with a fingerlike spine. Dorsal side of

1987]

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Fig. I. (Facing page and above.) Heads and lateral views of Chalepoxenus
spinosus (nov, comb.) (a, g— 9; d, k, \~~$; in k an epinotal spine, and in 1 the
postpetiolar spine are clearly visible), C. muellerianus (b, h— $; e, m— 5), and
C. kutteri (c, 1—$; f, n— g). Pictures were taken with a Wild Photomakroskop
M400.

122 Psyche [Vol.94

alitrunk with very long, not dense hairs, which are more devel-
oped in the petioles and the gaster. Tibiae and scapes with
sparse (not in all specimens preserved) outstanding hairs and a
fine pubescence which is mostly lacking in other body parts.
Body shining, head and thorax with long, sparse, longitudinal
wrinkles, one particularly long wrinkle along the inner margin
of the eye. Petioles smooth, gaster very smooth and shining.
Light brown, gaster and top of the head brown, 3.75-3.95 mm.
"Male: Head elongate, 1.25 times longer than wide, with
slightly vaulted sides and very large, very convex eyes.
Antennal clubs with very long segments, all funicular segments
much longer than wide. Clypeus elongate, reaching behind the
genae, its anterior border blunted in the middle, vaulted,
smooth like the triangular frontal area. Frontal carinae
straight, parallel, visible until the anterior ocellus, all ocelli very
large. Thorax narrow above, anterior part of mesonotum nar-
rowing. Alitrunk shining, with sparse longitudinal wrinkles,
petioles smooth, with ventral teeth as in the $, but smaller.
Hypopygium and squamulae long, leaf-shaped. Brown, legs
and antennae straw-yellow. 3.3-3.7 mm."

A comparison is made with other leptothoracine genera, and the
author stresses that Leonomyrma exhibits some characters of social
parasitic ants. Thus, the ventral projections of the petioles appear
similar to those in Formicoxenus, the long frontal carinae resemble
those of Chalepoxenus, the structure of the male antenna and the
wing venation are said to match those of Myrmoxenus, to which
Leonomyrma is closely related. It differs, however, from Myrmoxe-
nus by the dentate mandibles of males and the queens, the strong
epinotal spines, the rounded nodes, and the long and fine post-
petiolar spine. From Formicoxenus it is distinguished by the
number of antennal segments, shape of head, etc.; from Chale-
poxenus by lacking the long scrobes along the frontal carinae, much
stronger epinotal spines, and the long hairs; and from Epimyrma
also by the long hairs, number of antennal segments, and so on.

Thus, the most important difference between Leonomyrma and
Chalepoxenus refers to the antennal scrobes, since size and shape of
epinotal spines and the density and length of hairs usually are char-
acters varying widely within one genus. In the original description of

1987] Buschinger— Synonymy of Leonomyrma Arnoldi 123

Chalepoxenus, however, Menozzi (1922) explicitly writes: "frontal
carinae long, sub-parallel, and laterally confining an antennal
scrobe, which is little marked and much shorter than the antennal
scape" (translated from Italian). Direct comparison (Fig. 1) reveals
that there is literally no difference between the antennal scrobes of
Leonomyrma and Chalepoxenus.

In table 2 L. spinosa is compared with two Chalepoxenus species.
I choose for reference C. muellerianus and C. kutteri, because they
represent the two most different species in the genus. C. siciliensis
and C. insubricus closely resemble C. muellerianus, C. gribodoi was
already synonymized with the latter (Kutter 1973), and C. tramierih
close to C. kutteri {C&gmsLni 1983).

The comparison shows that there are some morphological differ-
ences between L. spinosa and Chalepoxenus species, but not more
than between the latter two. L. spinosa is sharing some characters
(postpetiolar spines in $ and $, long and acute epinotal spines in 9,
long body hairs) with C. kutteri, others (steeply ascending petiolar
node, erect tibial hairs) with C. muellerianus. No crucial differences
could be found which would justify the maintenance of a separate
genus for L. spinosa, whereas its species rank in the genus
Chalepoxenus appears sufficiently substantiated.

Since C. muellerianus is an active slavemaker (Ehrhardt 1980),
and also C. siciliensis, C. insubricus, and C. kutteri (Buschinger et
al., in prep.), we may predict that L. spinosa, too, will exhibit this
particular life habit. The original material consists of alate sexuals,
only, which were apparently caught during swarming. The lack of
workers in the sample, therefore, is not surprising*.

Summary

The monotypical genus Leonomyrma, described by Arnoldi 1968
from 4 9$ and 14 S$ of L. spinosa from East-Kasachstan, USSR, is

*Chalepoxenus brunneus Cagniant 1985, described from males and females from one
colony, is a workerless and thus not a slave-raiding species. We (A. Buschinger,
J. Heinze, H. Cagniant, X. Espadaler) collected 11 colonies at its type locality!
Tizi-n-Test, Great Atlas of Morocco, on May 6, 1987. None of them contained
Chalepoxenus workers, and their brood also consisted of male and female pupae
only. Thus, C. spinosus also might be truly workerless. [Added in proof. May, 1987].

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126 Psyche [Vol.94

synonymized with the genus Chalepoxenus Menozzi 1922. A mor-
phological comparison of the Leonomyrma holotype $ and an allo-
type S with material of Chalepoxenus muellerianus and C. kutteri
revealed a close similarity in most relevant characters. It may be
predicted that Chalepoxenus spinosus (nov. comb.) will be a slave-
making ant Hke the other species of the genus.

Acknowledgements

I am indebted to Dr. A. V. Antropov and the Zoological
Museum, Moscow, for having provided the type material of
Leonomyrma spinosa. The Deutsche Forschungsgeneinschaft has
generously supported our studies in Chalepoxenus.

References

Arnoldi, K. V.

1968. Wichtige Erganzungen zur Myrmecofauna (Hymenoptera, Formicidae)
der USSR, mit einigen Neubeschreibungen (in Russian, German Sum-
mary). Zool. J. 47: 1800-1822.
BuscHiNGER, A., W. Ehrhardt, K. Fischer, and J. Ofer

(in prep.) Biosystematic revision of the slavemaking ant genus Chalepoxenus.
Cagniant, H.

1983. Contribution a la connaissance des Fourmis Marocaines Chalepoxenus

tramieri, nov. sp.. Nouv. Rev. Ent. 13: 319-322.
1985. Contribution a la connaissance des Fourmis Marocaines: Chalepoxenus
brunneus n.sp. (Hymenoptera, Myrmicidae). Nouv. Rev. Ent. (N.S.) 2,
Fasc. 2: 141-146.
Ehrhardt, W.

1982. Untersuchungen zum Raubzugverhalten der sozialparasitischen Ameise
Chalepoxenus muellerianus (Finzi) (Hym., Formicidae). Zool. Anz. 208:
145-160.
Finzi, B.

1921. Primo contributo alia conoscenza della fauna mirmecologica della
Venezia Giulia. Boll. Soc. Ent. Ital. 53: 118-120.

KUTTER, H.

1973. Zur Taxonomie der Gattung Chalepoxenus (Hymenoptera, Formicidae,
Myrmicinae). Mitt. Schweiz. Ent. Ges. 46: 269-280.
Menozzi, C.

1922. Nota su un genere e nuova specie di Formica parassita. Atti Soc. Ital.
Sci. Nat. 61: 256-260.

MOller, G.

1923. Le formiche della Venezia Giulia e della Dalmazia. Boll. Soc. Adriat.
Sci. Nat. Trieste 28: 11-180.